I'm pretty sure that higher level DLA mobility is not allowable for mental health problems.
http://www.benefitsandwork.co.uk/news/186-new-genuinely-disabled-test-to-cut-dla-a-aa-awards
CFS is recognised by the DWP as a mental+ physical condition.
It has both physical and mental components.
I have no conditions other than CFS, and got high-rate DLA mobility.
https://www.gov.uk/government/uploa.../file/537346/a-z-adult-medical-conditions.pdf
Page 210. And 'severe functional restriction' on page 212.
These are all reasonably accurate descriptions, though of course they could be better.
Walking disorders are required (for DLA) to have some 'physical' basis - but this does not mean that it has to be musceloskeletal (assuming for the moment that there is no significant pain when walking, which separately qualifies).
The physical basis does not have to be medically understood, just that it cannot be 'purely mental' - this is a hideous definition, but in practice, it is usually accepted that CFS has 'some' physical element.
The version of the above guidance current in 2013 stated
The reality is that the disability of CFS/ME involves both physical and mental incapacity and it is important to ensure full consideration is given to all the disabling effects of the illness and an accurate assessment of care and mobility needs is made.
- the current does not explicitly state this.
I have had low-rate mobility component of DLA due to my CFS since 2010 or so, and last Febuary made a 'better' application requesting backdating, which eventually lead to a backdated award to Feb 2015 of the high rate of the mobility component.
http://www.disabilityrightsuk.org/h...s/case-law-summaries/attendance-allowance-and - an excerpt of a judgement on what the law is:
" a claimant may for example have physical back problems and also depression. If depression is due to her physical condition, at least in part, or if her physical condition is a material cause limiting her walking, albeit exacerbated by unconnected depression, then a tribunal is entitled to find any resultant walking difficulties are due to her physical condition as a whole".
The caselaw in this area is complex, and means that the legislation does not quite mean what it seems to on a bald reading.